1. Field of the Invention
The invention deals with singulators which are used for sorting goods. Such singulators are used to arrange a plurality of objects into one or more streams of objects which are serially arranged so that they can be moved and individually examined for further sorting or other processing. In particular, the present singulator is useful in sorting applications where it is important to avoid damaging the items being sorted. One example is citrus fruit sorting.
2. Related Art
The use of singulators in fruit sorting applications is well known. U.S. Pat. No. 4,726,898 discloses a singulator conveyor which uses rollers rotatably mounted to a chain drive. The roller conveyors may be spaced along the chain to accommodate fruit of various sizes, so that each item of fruit is carried by an adjacent roller conveyor. U.S. Pat. No. 4,091,931 discloses an aligning conveyor 28 defined by a plurality of parallel, side-by-side belts 58 constructed of resilient material. The aligning conveyor 28 receives tomatoes from side belts 16 and 18 and arranges the tomatoes into a plurality of side-by-side rows of serially arranged tomatoes.
Whether using rollers or belts, in conventional singulators the items being sorted undergo an abrupt transition at the end of the singulator belt when they are transferred into carrying cups for further sorting or processing. In such conventional systems, at the end of the belt each item is abruptly dropped into an individual carrying cup which moves the item along in the system. The abrupt drop causes fragile items such as fruit to be bruised, scratched, or otherwise damaged. In addition, the linear speed of fruit or other items moving along the belt is typically slower than the forward speed of the carrier cups. The carrier cups move at a higher rate of speed in order to maintain synchronism between the cups and the fruit dropping off the belt. Since the carrier cups are moving at a higher rate of speed, when an item falls into a cup, it is accelerated from its current linear speed. Since the item is dropped over a finite distance, its linear speed in the direction of travel may approach zero as the item drops from the belt. As a result of the difference in the forward travelling speed of the fruit and cup, the rear portion of the cup strikes the fruit or other item after it drops into the cup, further increasing the risk of damage to the fruit or other item.
Conventional approaches to reducing the amount of bruising or other damage resulting from singulation and sorting involve the use of soft padding and other shock absorbing materials. Conventional approaches fail to eliminate the source of the problem by controlling the dropping of items into the cups.